A typical Vista sidebar has a default configuration similar to the one shown, which includes a clock, RSS reader, and the image slideshow applet.
To adjust the properties of the Windows Sidebar you navigate to the Control Panel and click on the Configure Windows Sidebar icon. The Windows Sidebar Properties screen allows you to configure the sidebar to start when Vista starts, determine to which side it will align, and designate on which monitor it will display if you have a more than one monitor system. You can also see at a glance which gadgets are running currently.
To add gadgets to the sidebar, right-click on any empty space on the Windows Sidebar and select Add Gadgets... from the context menu.
That menu choice will take you to the Add Gadgets interface. From this window you can select and install gadgets you have already downloaded into your gadget gallery.
For most of the gadgets in your gallery, all you need to do to install and activate them is double click the corresponding icon on this window. For example, you can see I added Weather, Stock, and Media Player gadgets.
The Media Player gadget is an example of a third-party created gadget. These gadgets are made available to the public for free download on the Windows Live Web site. The easiest way to get there is to click the ""="">Get more gadgets online link on the bottom of you gadget gallery. That link takes you to the page shown.
Each gadget has options peculiar to it that you can modify. For example, the Weather gadget defaults to showing the temperature in Redman, WA. On the side of each gadget there is a wrench icon.